In the past two decades, environmental concerns and economics have encouraged, if not required, a return to significant and widespread reliance on paper recycling. It is estimated that, in 1950, over 30% of the fibers used in the paper and paperboard industry were derived from waste paper. By 1970, recycled, i.e., waste, paper accounted for only some 22-23% of the fibers used to create new paper and paperboard products, even as the volume of paper produced was rising dramatically.
There were any number of reasons for this large decline in the use of recovered paper, including post-World War II increases in the forest resources available to the paper industry, and serious practical problems faced in collecting, separating, and processing post-consumer waste paper. Because paper recycling declined after World War II even while demand for paper steadily increased, paper products have represented a major burden for solid waste management efforts. Although paper is "biodegradable" in the sense that it will break down under proper conditions given sufficient time, the very nature of modern landfills, wherein wastes are isolated from water and microbes necessary to stimulate biological and chemical breakdown, degradation of waste paper into carbon dioxide and water is unlikely to happen in meaningful amounts, again given the state of many current practices.
As has been increasingly recognized over the past two decades this means that unless the waste stream can be used as a source for paper products made from such waste, society will be threatened with burial in its own discarded, but in many cases perfectly reusable, post-consumer waste paper. For these reasons, interest in paper recycling has revived, as is evidenced by the many consumer paper products on the market bearing a logo identifying recycled paper products or otherwise indicating their manufacture, at least in part, from recycled materials. The challenge remains to convert, to the maximum extent practicable, an environmental problem into an environmentally friendly economic resource.
One of the most persistent problems plaguing paper recycling efforts is separation. Certain paper products are far more easy and inexpensive to process than others. For this reason, waste paper haulers may pay a premium for certain kinds of waste paper, such as recyclable white paper, but may refuse to pay for paper colored with permanent dyes, or even charge for hauling it away.
Attempting to sort the hundreds of tons of mixed paper refuse produced by even a moderate sized community is extremely labor intensive, and is thus economically prohibitive. Yet where, for example, the only difference between a high quality, desirable piece of waste paper and one considered unusable, "contaminated," or fit only for a less profitable use, is that the former is free of permanent dye whereas the latter is dyed, it can be appreciated that hand separation has heretofore been believed to be the only way available for sorting.
Although, at least theoretically, sorting waste paper into its constituent sub-categories could be accomplished at each location where waste paper is generated, the practical difficulties presented by such an approach are virtually insurmountable. Large institutions especially would be saddled with prohibitively expensive, onerous burdens if compelled to educate workers about, and then oversee, internal separation and disposal schemes. Moreover, even in the case of a highly motivated work force generally committed to the recycling program, the ongoing, consistent depositing of different categories of paper into specially designated receptacles situated about the work place would be at best a time consuming and thus impractical process.
Yet large and small institutions alike generate a tremendous amount of waste paper of different recycling qualities. The use of a multiplicity of more or less standardized paper forms in day to day operation is extremely common. Frequently, such forms are required to be filled out in duplicate to be routed and dispersed among persons or files both inside and outside the entity originating them. Of course, the most common method used for differentiating the various paper sheets comprising such forms is by color coding. Triplicate forms comprising white, yellow, and pink paper sheets, for example, are widely used.
Even where duplication of a particular form at the time it is generated is not necessary, institutions rely heavily on various standard forms, such as requisition forms, inventory sheets, medication schedules, etc. Color coding in such instances is used so that the proper form for a particular use or destination can be quickly and accurately selected out of an aggregation of forms, either from general office storage or from supplies maintained at the work station.
Other color coding exists where letter or other documents are prepared, whether by typing, printing or otherwise, in multiple copies, each of a different color. Where the sheets are colored by dye, it is not practical to recycle them. On the other hand, sheets made from white paper are recyclable, even if heavily written on, typed on, or printed.
Up to now, the clearly efficacious method of color coding business and other forms has been accomplished through the use of permanent dyes that impregnate the very fibers of the paper itself. Unfortunately, once dyed in this manner, the paper is degraded from the recycler's point of view, and cannot be processed economically into re-usable white paper by mixing with white waste paper and subsequently de-inking, pulping, bleaching and reconstituting such paper on a papermaking machine.
In view of these problems, it is the object of the present invention to provide businesses, hospitals, schools, and other institutions requiring specialized forms, which are often filled out in duplicate and dispersed to multiple recipients, with color-coding systems rendering the sheets readily distinguishable and distributable by color, and yet capable of being recycled with white paper without further separation.
Another object of the invention is to provide color-coded papers capable of being recycled as white paper, using conventional and inexpensive printing technology, wherein such sheets of paper are easily distinguished by color code from sheets of paper similarly coded with other colors, and wherein such sheets of paper are readily aggregated with other papers of the same color code, or with papers coded with different colors, for use as specialized forms requiring categorization by subject, recipient, or otherwise.
Another object of the invention is to provide color-coded sheets of paper wherein the color coding is imparted through the application to individual sheets of surface adhering ink amendable to standard de-inking methods used in processing waste paper for recycling.
A further object of the invention is to provide paper having color code areas such as the margins or other areas made by printing with non-dye type inks permitting easy recycling, as well as having substantially color-free image or message-receiving areas. The color-coded area, which may but need not comprise the entire face of the sheet, may be made by various known techniques, including half-tone or other screen printing, using pre-diluted inks creating a tinted appearance, or the like.
A still further object of the invention is to provide recyclable, color-coded paper at low cost.
The foregoing and other objects and advantages of the invention are achieved in practice by providing a paper product, usually in the form of an array of color-coded papers capable of being individually color-coded by using a non-dying ink able to be removed from the paper fibers by conventional de-inking processes, whereby the individually color-coded sheets may be recycled as white paper, whether mixed with non-color-coded paper or otherwise.
The exact manner in which the foregoing and other objects and advantages of the invention are carried into practice will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the invention set forth by way of example, and shown in the accompanying drawings, wherein like reference numbers indicate corresponding parts throughout.